Previous valve cartridges of the above type are disadvantageous mainly in that they have a long and space demanding valve barrel for introduction in a socket. portion in the directional valve housing. This is mainly due to the fact that the pilot flow restricting means comprises a nozzle like plug threaded into the end portion of the pilot valve bore. Accordingly, this plug type flow restricting means requires that the valve barrel is extended beyond the length needed just for the axial shifting movement of the pilot valve element.
Another disadvantage inherent in the above mentioned prior art pilot valve cartridge is that a thread has to be cut in the end portion of the valve bore for mounting of the flow restricting plug, and an outer circumferential groove has to be formed on the valve barrel for supporting the seal ring separating the pilot flow opening from the other lateral openings.
The above disadvantages are avoided by the invention as it is defined in the claims.
A preferred embodiment of the invention is described below in detail with reference to the accompanying drawings.